Method for manufacturing multilayer ceramic condenser

ABSTRACT

Disclosed are a multilayer ceramic condenser and a method for manufacturing the same. There is provided a multilayer ceramic condenser including: a multilayer main body in which a plurality of dielectric layers including a first side, a second side, a third side, and a fourth side are stacked; a first cover layer and a second cover layer forming the plurality of dielectric layers; a first dielectric layer disposed between the first cover layer and the second cover layer and printed with a first inner electrode pattern drawn to the first side; a second dielectric layer alternately stacked with the first dielectric layer and printed with a second inner electrode pattern drawn to the third side; and a first side portion and a second side portion each formed on the second side and the fourth side opposite to each other.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Divisional of U.S. patent application Ser. No.13/191,890, filed on Jul. 27, 2011, now U.S. Pat. No. 8,804,305, whichclaims the priority of Korean Patent Application No. 10-2010-0125069filed on Dec. 8, 2010, the disclosures of which are incorporated hereinby reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a multilayer ceramic condensor and amethod for manufacturing the same, and more particularly, to a methodfor manufacturing a multilayer ceramic condenser having improvedreliability by securing the durability of a chip, and a multilayerceramic condenser manufactured by the same.

Description of the Related Art

A condenser, a device capable of storing electricity, basically storeselectricity in electrodes thereof by applying opposite voltages toopposing electrodes. When DC voltage is applied thereto, current flowsinto a condenser, while electricity is stored therein, yet when thestorage of electricity is completed, current does not flow in thecondenser. Meanwhile, when AC voltage is applied to the electrodes of acondenser, AC current continuously flows in the condenser while thepolarity of the electrode is alternated.

The condenser may be classified as an aluminum electrolytic condenser,in which electrodes are made of aluminum and a thin oxide layer isprovided between the aluminum electrodes, a tantalum condenser, usingtantalum as an electrode material, a ceramic condenser, using a high-Kdielectric such as barium titanate between electrodes, a multi layerceramic condenser (MLCC), using a multilayer structure having high-Kceramic as a dielectric provided between electrodes, a film condenserusing a polystyrene film as a dielectric between electrodes, or thelike, according to a type of an insulator provided between electrodes.

Among others, the multilayer ceramic condenser can be implemented tohave a small size while having excellent temperature and frequencycharacteristics, such that it has been frequently used for variousapplications such as a high frequency circuit, and the like.

In the multilayer ceramic condenser according to the related art, alaminate may be formed by stacking a plurality of dielectric sheets,outer electrodes having different polarities may be formed on theoutside ends of the laminate, and inner electrodes alternately stackedin the laminate may be electrically connected to each of the outerelectrodes.

Recently, as electronic products have become small and highlyintegrated, research into miniaturizing and highly integrating themultilayer ceramic condenser has been frequently conducted. Inparticular, various attempts to improve the connection between the innerelectrodes while thinning and increasing the stacking amount of thedielectric layers in order to implement a high-capacity and small-sizedmultilayer ceramic condenser have been conducted.

In particular, the side portion of the dielectric layer, manufactured byvarious methods, is provided to secure the durability of the chips, Inparticular, an edge portion of the chip is the most important portion inorder to prevent the occurrence of cracking in the chips and to securethe reliability thereof.

SUMMARY OF THE INVENTION

An aspect of the present invention provides a multilayer ceramiccondenser capable of securing a thin dielectric layer in order toimplement a highly stacked and small-sized multilayer ceramic condenserand preventing a thickness of an edge portion from being excessivelythick at an unwanted portion while securing the thickness of the edgeportion, and a method for manufacturing the same.

According to an aspect of the present invention, there is provided amultilayer ceramic condenser, including: a multilayer main body in whicha plurality of dielectric layers including a firs side, a second side, athird side, and a fourth side are stacked; a first cover layer and asecond cover layer forming the plurality of dielectric layers; a firstdielectric layer disposed between the first cover layer and the secondcover layer and printed with a first inner electrode pattern drawn tothe first side; a second dielectric layer alternately stacked with thefirst dielectric layer and printed with a second inner electrode patterndrawn to the third side; and a first side portion and a second sideportion each formed on the second side and the fourth side opposite toeach other.

The first side portion or the second side portion may be formed byapplying slurry thereto.

The maximum thickness of the first side portion or the second portionmay be set to be 10 μm to 30 μm.

The maximum thickness of the first side portion or the second portionmay be set to be 10 μm to 20 μm.

The thickness of an edge portion contacting corners of the multilayermain body at the first side portion or the second side portion may be 2μm or more.

The thickness of the first cover layer or the second cover may be 10 μmor less.

The multilayer ceramic condenser may further include a first outerelectrode and a second outer electrode each formed on the first side andthe third side.

According to another exemplary embodiment of the present invention,there is provided a method for manufacturing a multilayer ceramiccondenser, including: preparing a multilayer main body including a firstcover layer and a second cover layer, a plurality of first dielectriclayers formed between the first cover layer and the second cover layerand printed with first inner electrode patterns, a plurality of seconddielectric layers alternately stacked with the plurality of firstdielectric layers and printed with second inner electrode patterns, anda first side, a second side, a third side, and a fourth side; attachinga first film and a second film to the first cover layer and the secondcover layer of the multilayer main body; forming a first side portionand a second side portion on the second side and the fourth side,respectively, by dipping the multilayer main body attached with thefirst film and the second film in slurry; and removing the first filmand the second film attached to the multilayer main body.

The first film or the second film may be an adhesive film.

The first film or the second film may be an ultraviolet (UV) adhesivefilm.

The thickness of the first side portion and the second side portion maybe controlled by adjusting the number of dipping.

The dipping of the multilayer main body may be performed before thefirst side and the third side are cut off.

The maximum thickness of the first side portion or the second portionmay be set to be 10 μm to 30 μm.

The maximum thickness of the first side portion or the second portionmay be set to be 10 μm to 20 μm.

The thickness of the edge portion contacting corners of the multilayermain body at the first side portion or the second side portion may beset to be 2 μm or more.

The thickness of the first cover layer or the second cover may be set tobe 10 μm or less.

The method for manufacturing a multilayer ceramic condenser may furtherinclude forming a first outer electrode and a second outer electrode onthe first side and the third side, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a perspective view of a multilayer ceramic condenser accordingto an exemplary embodiment of the present invention;

FIG. 2 is an exploded perspective view of a multilayer ceramic condenseraccording to an exemplary embodiment of the present invention;

FIG. 3 is a perspective view showing a multilayer main body of amultilayer ceramic condenser according to an exemplary embodiment of thepresent invention;

FIG. 4 is a cross-sectional view taken along line A-A′ of the multilayermain body;

FIG. 5 is a cross-sectional view showing a multilayer main body formedwith a first side portion and a second portion according to an exemplaryembodiment of the present invention; and

FIG. 6 is a perspective view showing a multilayer main body formed witha first side portion and a second portion according to an exemplaryembodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Exemplary embodiments of the present invention will be described withreference to the accompanying drawings. The invention may, however, beembodied in many different forms and should not be construed as beinglimited to the embodiments set forth herein; rather, these embodimentsare provided so that this disclosure will be thorough and complete, andwill fully convey the concept of the invention to those skilled in theart. In the drawings, the thicknesses of layers and regions areexaggerated for clarity.

Further, throughout the drawings, the same or similar reference numeralswill be used to designate the same components or like components havingthe same functions in the scope of the similar idea.

In addition, unless explicitly described to the contrary, the word“comprise” and variations such as “comprises” or “comprising,” as wellas the word “include” and variations such as “includes” and “including,”will be understood to imply the inclusion of stated elements but not theexclusion of any other elements.

Hereinafter, a multilayer ceramic condenser and a method formanufacturing the same according to an exemplary embodiment of thepresent invention will be described with reference to FIGS. 1 to 6.

FIG. 1 is a perspective view of a multilayer ceramic condenser accordingto an exemplary embodiment of the present invention, FIG. 2 is anexploded perspective view of a multilayer ceramic condenser according toan exemplary embodiment of the present invention, FIG. 3 is aperspective view showing a multilayer main body of a multilayer ceramiccondenser according to an exemplary embodiment of the present invention,FIG. 4 is a cross-sectional view taken along line A-A′ of the multilayermain body, FIG. 5 is a cross-sectional view showing a multilayer mainbody formed with a first side portion and a second portion according toan exemplary embodiment of the present invention, and FIG. 6 is aperspective view showing a multilayer main body formed with a first sideportion and a second portion according to an exemplary embodiment of thepresent invention.

Referring to FIG. 1 showing a multilayer ceramic condenser according toan exemplary embodiment of the present invention, a multilayer ceramiccondenser 1 includes a multilayer main body 20 in which a plurality ofdielectric layers are stacked, a first outer electrode 10 a, and asecond outer electrode 10 b.

The multilayer main body 20 is formed by stacking a plurality ofdielectric layers and has a structure in which the plurality ofdielectric layers are alternately stacked with the first inner electrodeand the second inner electrode.

The multilayer main body 20 may be formed to include a first side, asecond side, a third side, and a fourth side in sequence. The first sideand the third side, which are formed to be opposite to each other, areeach connected to the first outer electrode 10 a and the second outerelectrode 10 b and the second side and the fourth side are disposed tobe opposite to each other.

A first inner electrode and a second inner electrode are each formed tobe drawn to the first side and the third side, such that they may beelectrically connected to the first outer electrode 10 a and the secondouter electrode 10 b.

The plurality of dielectric layers configuring the multilayer main bodymay be manufactured as a high-K ceramic green sheet.

The first outer electrode 10 a and the second outer electrode 10 b maybe made of materials having excellent electric conductivity and mayserve to electrically connect a first inner electrode pattern, a secondinner electrode pattern, or other various patterns formed in themultilayer ceramic condenser to outer devices, but is not limitedthereto. Therefore, the first outer electrode 10 a and the second outerelectrode 10 b may be made of a material such as Ni, Ag, Pd, or thelike.

Referring to FIG. 2 showing an exploded perspective view of a multilayerceramic condenser according to an exemplary embodiment of the presentinvention, the multilayer main body 20 is configured to include a firstcover layer 100 a and a second cover layer 100 b disposed on the top andbottom surfaces thereof, first dielectric sheets 201 and 208 printedwith a first inner electrode pattern 30 a, and second dielectric sheets202 and 209 printed with second inner electrode pattern 30 b.

The multilayer main body 20, in which the plurality of dielectric layersare stacked, includes the first cover layer 100 a and the second coverlayer 100 b formed on the top and bottom portions thereof and theplurality of dielectric sheets 201, 202, 208, and 209 disposed betweenthe first cover layer 100 a and the second cover layer 100 b. Here theplurality of dielectric layers are manufactured in the form of theceramic green sheet and then, are subjected to a firing process and astacking process.

The ceramic green sheet may be manufactured by applying a ceramic pasteincluding ceramic powder, an organic binder including ethyl cellulose,polyvinyl butyral, or the like, and an organic solvent.

The ceramic powder is a high-K material. Without being thereto as theceramic powder a barium titanate-based material, a lead complexPerovskite-based material, a strontium titanate-based material, or thelike may be used, preferably, a barium titanate powder may be used.

The first inner electrode pattern 30 a and the second inner electrodepattern 30 b may be made of conductive metals having excellent electricconductivity. For example, the conductive metal may include at least oneselected from the group consisting of Ni, Cu, Pd and an alloy thereof,but not limited thereto.

The multilayer main body 20 is configured to include the first coverlayer 100 a and the second cover layer 100 b formed on the top andbottom portions thereof and the plurality of first dielectric layers 201and 208 printed with the first inner electrode patterns, and theplurality of second dielectric layers 202 and 209 printed with thesecond inner electrode patterns. The first dielectric layers 201 and 208and the second dielectric layers 202 and 209 are alternately stackedwith each other, such that the first inner electrode patterns 30 a maybe formed to be drawn to the first side and the second inner electrodepatterns 30 b may be formed to be drawn to the third side.

FIG. 3 is a perspective view showing a multilayer main body formed bystacking the plurality of dielectric layers as shown in FIG. 2.

Referring to FIG. 3, the first cover layer 100 a and the second coverlayer 100 b are formed on the top and bottom surfaces of a multilayermain body 120 and the first dielectric layer and the second dielectriclayer are alternately stacked therebetween such that the first innerelectrode patterns 30 a may be formed to be drawn to the first side andthe second inner electrode patterns 30 b may be formed to be drawn tothe third side.

In this case, direction A-A′ is a direction of the second side and thefourth side and both the first inner electrode patterns 30 a and thesecond inner electrode patterns 30 b are exposed to the second side andthe fourth side.

The first cover layer 100 a and the second cover layer 100 b are formedon the top and the lowermost portions of the dielectric layers printedwith the plurality of inner electrode patterns to serve to protect thepatterns formed therein from the outside.

Although the first inner electrode patterns 30 a or the second innerelectrode patterns 30 b are drawn to the first side and the third side,respectively, the first side is provided with the first outer electrode10 a and the third side is provided with the second outer electrode 10b, such that the first inner electrode patterns 30 a and the secondinner electrode patterns 30 b may be protected from being exposed to theoutside, through the first outer electrode 110 a and the second outerelectrode 110 b

However, since the first inner electrode patterns 30 a and the secondinner electrode patterns 30 b are formed to be exposed to the secondside and the fourth side, there is a need to protect the inner electrodepatterns formed therein by disposing separate side portions in thesecond side and the fourth side.

In order to form the side portions, the multilayer main body 120 may bedipped in slurry including a dielectric ceramic.

The slurry may include a ceramic powder, an organic binder, and anorganic solvent. The ceramic powder may use a material having excellentheat resistance and durability and wide working tolerance when formingthe side portions, as a high-K material.

The ceramic powder is not limited thereto, but a barium titanate-basedmaterial, a lead complex Perovskite-based material, a strontiumtitanate-based material, or the like, may be used, preferably, thebarium titanate powder may be used.

The organic binder is to secure the dispersibility of the ceramic powerin the slurry. Without being limited thereto, as the organic binder,ethyl cellulose, polyvinyl butyral, and a mixture thereof may be used.

As described above, when the multilayer main body 120 is dipped in theproduced slurry, the slurry is applied to the surface of the multilayermain body 120, on which the multilayer main body 120 is contacted to theslurry, such that the side portions may be formed. Further, in order toform the multilayer main body 120 having the desired thickness, thedesired amount of slurry may be applied to the multilayer main body 120by repeating the dipping and the drying.

When the multilayer main body 120 is dipped in the slurry, the slurryshould not be applied to the first side and the third side of themultilayer main body 120 since the first side and the third side of themultilayer main body 120 are provided with the outer electrodes.Therefore, the multilayer main body 120 may be dipped in the slurry byattaching a film to the first side and the third side so that the firstside and the third side are not exposed to the outside. Without beinglimited thereto, the first side and the third side may be dipped in anon-exposed state before the first side and the third are cut off.

When the multilayer main body 120 is dipped, the first cover layer 100a, the second cover layer 100 b, the second side, and the fourth side ofthe multilayer main body 120 are exposed to the outside, such that theslurry may be applied thereto.

When the slurry is applied to the first cover layer 100 a and the secondcover layer 100 b, the thicknesses of the first cover layer 100 a andthe second cover layer 100 b are excessively thick and the volume of thechip may be excessively large accordingly.

Referring to FIG. 4, according to an exemplary embodiment of the presentinvention, a first film 110 a and a second film 110 b may be attached tothe first cover layer 100 a and the second cover layer 100 b,respectively.

According to the exemplary embodiment of the present invention, each ofthe first film 110 a and the second film 100 b may be an adhesive film.

The adhesive film is a detachable film, such that it may be easilyattached to the first cover layer 100 a and the second cover layer 100 band easily removed therefrom after being dipped in the slurry. When thefilm such as the adhesive film is attached to the cover layer, theslurry is not applied to the cover layer but is applied to the adhesivefilm. Thereafter, when the film is removed, the slurry applied theretois removed together, such that it is possible to prevent the slurry frombeing applied to the cover layers.

According to an exemplary embodiment of the present invention, the firstfilm and the second film may be an ultraviolet (UV) adhesive film. TheUV adhesive film is a film that may be easily attached to the coverlayers while maintaining the adhesion before irradiating ultravioletrays thereto and may be easily removed therefrom by applying the slurryand then irradiating the ultraviolet rays thereto to remove the adhesionof the UV adhesive film.

According to an exemplary embodiment of the present invention, the firstfilm 110 a and the second film 110 b may each be attached to the firstcover layer 110 a and the second cover layer 100 b, such that the slurrymay not attached on the first film 110 a and the second film 110 b whenbeing dipped in the slurry.

Referring to FIG. 5, the slurry is attached to only the second side andthe fourth side, thereby forming a first side portion 150 a and a secondside portion 150 b.

Referring to FIGS. 5 and 6, the second side and the fourth sidecorresponding to direction A1-A1′ of the multilayer main body 120 of themultilayer ceramic condenser may be provided with the first side portion150 a and the second side portion 150 b.

The thicknesses of the first side portion 150 a and the second sideportion 150 b may be controlled according to the number of dipping.Therefore, as the number of dipping is increased, the thicknesses of thefirst side portion 150 a and the second side portion 150 b may bethicker.

In the case of the multilayer ceramic condenser according to theexemplary embodiment of the present invention, the first side and thethird side corresponding to direction B-B′ may be provided with thefirst outer electrode and the second outer electrode and the second sideand the fourth side corresponding to direction A1-A1′ may be providedwith the first side portion 150 a and the second side portion 150 b.

In particular, in the case of the multilayer main body 120, in order toprotect the plurality of electrode patterns formed therein, the top andlowest portions of the plurality of dielectric layers may be providedwith the first cover layer 100 a and the second cover layer 100 b andthe second side and the fourth side of the multilayer main body 120 maybe provided with the first side portion 150 a and the second sideportion 150 b.

Therefore, the chip having the excellent durability and preventing thecrack occurrence may be produced by securing the thickness of the sideportion of the chip, in particular, the edge portion corresponding tothe end of the side portion.

In particular, referring to FIG. 5, when the maximum thickness of theside portion of the multilayer main body 120 according to the presentinvention is referred to as d1 and the thickness of the edge portion,i.e., the portion contacting the corner portions of the multilayer mainbody 120 at the side portions is referred to as d2, the d1 and d2 maysatisfy the following Equations 1 and 2.10 μm≦d1≦30μm  [Equation 1]2 μm≦d2≦d1  [Equation 2]

According to the exemplary embodiment of the present invention, themaximum thickness of the side portion of the multilayer main body 120may be set to be 10 μm or more in order to secure the strength anddurability of the chip for protecting the patterns formed in themultilayer main body.

However, if the maximum thickness of the side portion exceeds 30 μm, aspace capable of forming the inner electrode patterns is narrow, suchthat it is difficult to implement the high capacity. Therefore, themaximum thickness of the side portion may be 30 μm or less and in orderto maximize the capacity, the maximum thickness thereof may be set to be20 μm or less.

In addition, the thickness of the side portion, in particular, thethickness of the edge may be set to be 2 μm or more. If the thickness ofthe edge portion is below 2 μm, the radiating crack may occur whenconnecting to the outer electrode and it is difficult to secure moistureresistance from the outside. Therefore, the thickness of the edgeportion may be set to be 2 μm or more.

In order to implement the high capacity, the thickness of the edgeportion may be thinner than that of the side portion corresponding tod1.

According to an exemplary embodiment of the present invention, thethickness of the first cover layer and the second cover layer may be setto be 10 μm or less even though the first side portion and the secondside portion are formed to have a thickness as above.

Since the first cover layer and the second cover layer are attached withthe first film and the second film and the first film and the secondfilm are removed after the process of forming the side portions, thethicknesses of the dielectric layers may be maintained with the coverlayers being not affected by the application of slurry.

According to an exemplary embodiment of the present invention, when thethickness of the cover layers is set to be 10 μm or more, it isdifficult to implement the high capacity, such that the thickness of thecover layers may be set to be 10 μm or less.

According to an exemplary embodiment of the present invention, the firstside portion and the second side portion are formed at two surfaces ofthe chip, thereby securing the thickness corresponding to the margin ofthe chip and ensuring the durability and moisture resistance of thechip.

Further, according to an exemplary embodiment of the present invention,the thickness of the edge portion could be secured, thereby preventingthe deformation of the chip, such as the radiating crack, or the like.

Further, according to an exemplary embodiment of the present invention,the cover layer having a thin thickness could be secured while thethicknesses of the side portion and the edge portion are ensured.Therefore the chip with the strong durability may be manufactured, whilehaving the high capacity.

In the case of the multilayer ceramic condenser, according to anexemplary embodiment of the present invention, the side portions havingthe desired thickness could be simply formed on only the sides oppositeto each other and accordingly, the super-capacity multi-layer ceramiccondenser could be implemented, while improving the reliability of thechip.

As set forth above, according to the method for manufacturing amultilayer ceramic condenser according to the exemplary embodiments ofthe present invention, the side portions of the multilayer main bodycould be formed at a desired thickness, thereby securing the thicknessof the edge portion. Further, the present invention can prevent thethickness of the cover portions from being excessively thick.

In addition, according to the exemplary embodiments of the presentinvention, slurry could be applied to only a desired surface by a simplemethod, thereby securing the thickness of the side portion, inparticular, the edge portion. In particular, the amount of slurry andthe number of dipping could be controlled, thereby forming the sideportion having the desired thickness.

While the present invention has been shown and described in connectionwith the exemplary embodiments, it will be apparent to those skilled inthe art that modification and variation can be made withough departingfrom the spirit and scope of the invention as defined by the appendedclaims.

What is claimed is:
 1. A method for manufacturing a multilayer ceramiccondenser, comprising: preparing a multilayer main body including afirst cover layer, a second cover layer, a plurality of first dielectriclayers formed between the first cover layer and the second cover layerand printed with first inner electrode patterns and a plurality ofsecond dielectric layers alternately stacked with the plurality of firstdielectric layers and printed with second inner electrode patterns, anda first side, a second side, a third side, and a fourth side, whereineach of the second side and the fourth side intersects both the firstand second inner electrode patterns, the first side intersects the firstinner electrode pattern, and the third side intersects the second innerelectrode pattern; attaching a first film and a second film to the firstcover layer and the second cover layer of the multilayer main body;forming a first side portion and a second side portion on the secondside and the fourth side, respectively, by dipping the multilayer mainbody attached with the first film and the second film in slurry, whereinthe slurry includes a ceramic powder including at least one selectedfrom a barium titanate-based material, a lead complex Perovskite-basedmaterial and a strontium titanate-based material; and removing the firstfilm and the second film attached to the multilayer main body, whereinthe slurry is a dielectric.
 2. The method of claim 1, wherein the firstfilm or the second film is an adhesive film.
 3. The method of claim 1,wherein the first film or the second film is an ultraviolet (UV)adhesive film.
 4. The method of claim 1, wherein a thickness of thefirst side portion and the second side portion is controlled byadjusting the number of dipping.
 5. The method of claim 1, wherein thedipping of the multilayer main body is performed before the first sideand the third side are cut off.
 6. The method of claim 1, wherein amaximum thickness of the first side portion or the second portion is 10μm to 30 μm.
 7. The method of claim 1, wherein a maximum thickness ofthe first side portion or the second portion is 10 μm to 20 μm.
 8. Themethod of claim 1, wherein a thickness of an edge portion contactingcorners of the multilayer main body at the first side portion or thesecond side portion is 2 μm or more.
 9. The method of claim 1, wherein athickness of the first cover layer or the second cover layer is 10 μm orless.
 10. The method of claim 1, further comprising foaming a firstouter electrode and a second outer electrode on the first side and thethird side, respectively.